Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755624AbYHSXUP (ORCPT ); Tue, 19 Aug 2008 19:20:15 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751777AbYHSXUD (ORCPT ); Tue, 19 Aug 2008 19:20:03 -0400 Received: from ppsw-5.csi.cam.ac.uk ([131.111.8.135]:48104 "EHLO ppsw-5.csi.cam.ac.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751224AbYHSXUB (ORCPT ); Tue, 19 Aug 2008 19:20:01 -0400 X-Cam-AntiVirus: no malware found X-Cam-SpamDetails: not scanned X-Cam-ScannerInfo: http://www.cam.ac.uk/cs/email/scanner/ Message-ID: <48AB551D.6010708@citrix.com> Date: Wed, 20 Aug 2008 00:19:57 +0100 From: Alex Nixon User-Agent: Thunderbird 2.0.0.16 (Windows/20080708) MIME-Version: 1.0 To: Yinghai Lu CC: Ingo Molnar , Jeremy Fitzhardinge , Linux Kernel Mailing List Subject: Re: [PATCH] X86: Change the default value of nr_irqs from 32 to NR_IRQs References: <48AAFAE4.7070409@citrix.com> <86802c440808191044h74871ba1u62330dae18599436@mail.gmail.com> <0E902970173AF84089673FA54B7FE78A2CA11D@lonpexch01.citrite.net> <86802c440808191124v39ce2aa9rb548d3bdd75ca25c@mail.gmail.com> <48AB11A3.4060102@citrix.com> <86802c440808191200u364ffd86h49af661e58d20ea3@mail.gmail.com> <48AB241A.4030706@citrix.com> <86802c440808191352g75c99737kcb8c9c20d59c8f7b@mail.gmail.com> In-Reply-To: <86802c440808191352g75c99737kcb8c9c20d59c8f7b@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 914 Lines: 23 Yinghai Lu wrote: > when !CONFIG_HAVE_SPARSE_IRQ, with dyn_array, could allocate irq_desc > and etc as less as possible. > when CONFIG_HAVE_SPARESE_IRQ, no actually meaning for nr_irqs. > > YH So I believe the only case this affects is !CONFIG_HAVE_SPARSE_IRQ The worry is that with CONFIG_HAVE_DYN_ARRAY we may waste memory by pre-allocating more irq_descs than may be necessary (NR_IRQs vs 32)? With !CONFIG_HAVE_DYN_ARRAY however, a static array of size NR_IRQS is allocated instead - so doesn't defaulting nr_irqs back to NR_IRQS just revert to the old behaviour (with the exception of the irq_descs being allocated in pre_alloc_dyn_array instead)? - Alex -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/